Human milk is considered the ‘golden standard’ for infant nutrition. Processing animal milk, for example cows' milk, to more resemble the composition of human milk is known in the art. Such processing is known in the art as ‘humanizing’ animal milk. The process of humanizing animal milk involves changing the ratio of casein:whey proteins as found in animal milk (e.g. approximately 80:20 for cow's milk) to the desired ratio for infant nutrition, as found in human milk (preferably between 75:25 and 30:70). In addition, the mineral content of animal milk is typically higher that the content found in human milk. Thus humanization of animal milk requires the reduction of the mineral content.
Preparation of products suitable for use in infant nutrition typically involves blending of various individually purified components in the appropriate ratios, either wet or dry. Current manufacturing processes require multiple dairy ingredients from intermediate suppliers, including skim milk or a concentrate thereof (including skim milk powder), demineralised whey or a concentrate thereof (including demineralised whey powder), whey protein concentrates or isolates (normally as powders), and pure grade lactose (typically in powder form) to formulate a nutritionally balanced infant formula.
WO 96/08155 describes a process for treating skim milk for the manufacture of cheese and milk powders, wherein whey proteins are removed from skim milk by microfiltration and further treatment includes ultrafiltration.
U.S. Pat. No. 5,503,865 discloses a process for treating skim milk, comprising microfiltration or ultrafiltration. The permeate thereof may be demineralised by for example ion exchange and/or electrodialysis in order to make it suitable to be used in baby products.
U.S. Pat. No. 4,497,836 discloses a process wherein whey is subjected to ultrafiltration, and the permeate thereof is subjected to electrodialysis or ion exchange.
WO 2001/93689 discloses a process wherein milk serum is subjected to ultrafiltration, and the permeate thereof is subjected to diafiltration. The ultrafiltration retentate is combined with the diafiltration retentate in the production of infant milk formulae, by mixing the combined product with milk powder.
EP 1133238 describes a process wherein animal milk is subjected to microfiltration through a membrane having a porosity of 0.1-0.2 micrometer, after which the microfiltration permeate comprising whey proteins is demineralised by electrodialysis. The mineral content of the electrodialyzed microfiltration permeate is very low, and subsequent fortification with minerals and trace elements is required to obtain an infant formula.